From: Michal Marek <mmarek@suse.cz>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Sam Ravnborg <sam@ravnborg.org>,
Josh Triplett <josh@joshtriplett.org>,
linux-kbuild <linux-kbuild@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Rashika Kheria <rashika.kheria@gmail.com>
Subject: Re: #pragma once?
Date: Tue, 07 Jan 2014 11:09:11 +0100 [thread overview]
Message-ID: <52CBD247.8080508@suse.cz> (raw)
In-Reply-To: <CAMuHMdWPq4YgUoxE1GvQbsEJQu-wjhpra2fRDgkNfEZP0sqpVQ@mail.gmail.com>
On 2014-01-07 10:48, Geert Uytterhoeven wrote:
> Furthermore some userspace may rely on doing #define XXX to avoid
> including a specific kernel header (yes, it's ugly).
This pattern is also sometimes used:
$ head -6 include/linux/spinlock_up.h
#ifndef __LINUX_SPINLOCK_UP_H
#define __LINUX_SPINLOCK_UP_H
#ifndef __LINUX_SPINLOCK_H
# error "please don't include this file directly"
#endif
And there is nothing ugly about it. So #pragma once is probably a good
idea for most headers that are not exposed to userspace. But making it a
requirement in scripts/checkpatch.pl or Documentation/CodingStyle means
that it will become hard to defend the few legitimate uses of ifndef
guards against people who have a printed copy of checkpatch.pl under
their pillow.
Michal
next prev parent reply other threads:[~2014-01-07 10:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-06 20:47 #pragma once? Josh Triplett
2014-01-06 21:00 ` Andrew Morton
2014-01-06 21:09 ` Josh Triplett
2014-01-06 21:33 ` Theodore Ts'o
2014-01-06 21:50 ` Dave Jones
2014-01-07 5:55 ` Sam Ravnborg
2014-01-07 9:48 ` Geert Uytterhoeven
2014-01-07 10:09 ` Michal Marek [this message]
2014-01-07 10:38 ` Josh Triplett
2014-01-07 10:50 ` Josh Triplett
2014-01-07 10:50 ` Josh Triplett
2014-01-12 16:14 ` Patrick Palka
2014-01-13 5:53 ` Josh Triplett
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